size_t strnlen(const char *s, size_t maxlen);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.10:
_XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
The strnlen() function returns the number of bytes in the string
pointed to by s, excluding the terminating null byte ('\0'), but at
most maxlen. In doing this, strnlen() looks only at the first maxlen
bytes at s and never beyond s+maxlen.
The strnlen() function returns strlen(s), if that is less than maxlen,
or maxlen if there is no null byte ('\0') among the first maxlen bytes
pointed to by s.
This page is part of release 3.54 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-05-10 STRNLEN(3)
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